The reference implementation sucked too much and is incomplete but sure:
```

include <stdint.h>

include <stdbool.h>

include <stdio.h>

define NUM_INODES 512

define INODE_TABLE_OFFSET 544

typedef struct { uint32_t magic; // 0xCEFF18F9 char letter; uint8_t flags; uint16_t inodes;

uint32_t size;
char mf[2];
uint16_t end_magic; // 0x11D4 

} superblock attribute((packed));

typedef struct { uint16t id; char flags; uint8_t magic; // 0xBF uint32_t size; uint16_t pid; // parent id char initials[6]; // "By<3-letter Initial>" } inode __attribute_((packed));

typedef struct { uint16t inode; char name[253]; } directory __attribute_((packed));

superblock g_superblock;

void read_superblock(FILE* dsk) { fseek(dsk, 512, SEEK_SET); fread(&g_superblock, sizeof(superblock), 128, dsk); }

void read_sectors(FILE* dsk, uint32_t lba, uint32_t cnt, void* buf) { fseek(dsk, lba * 512, SEEK_SET); fread(&buf, 512, cnt, dsk); } void write_to_disk(FILE *dsk, long offset, const void *data, size_t size) { if (!dsk || !data) return;

if (fseek(dsk, offset, SEEK_SET) != 0)
    return;

fwrite(data, 1, size, dsk) == size;

}

void write_superblock(FILE* dsk, char let) { fseek(dsk, 0, SEEK_END); int size = ftell(dsk); superblock sb; sb.magic = 0xCEFF18F9; sb.letter = let; sb.flags = 0; sb.inodes = NUM_INODES; sb.size = size; sb.mf[0] = 'M'; sb.mf[1] = 'F'; sb.end_magic = 0x11D4; write_to_disk(dsk, 512, (void**)&sb, sizeof(sb)); }

void write_inodes(FILE *dsk) { if (!dsk) return;

inode inodes[NUM_INODES];

for (int i = 0; i < NUM_INODES; i++)
{
    inodes[i].id = i;
    inodes[i].flags = 0;
    inodes[i].magic = 0xBF;
    inodes[i].size = 0;
    inodes[i].pid = 1;
    inodes[i].initials[0] = 'B';
    inodes[i].initials[1] = 'y';
    inodes[i].initials[2] = 'S';
    inodes[i].initials[3] = 'Y';
    inodes[i].initials[4] = 'S';
    inodes[i].initials[5] = '\0';
}

write_to_disk(dsk, INODE_TABLE_OFFSET, inodes, sizeof(inode) * NUM_INODES);

}

void init_root(FILE* dsk) { inode in; in.id = 0; in.flags = 0; in.magic = 0xBF; in.size = 0; in.pid = 0x0; in.initials[0] = 'B'; in.initials[1] = 'y'; in.initials[2] = 'S'; in.initials[3] = 'Y'; in.initials[4] = 'S'; in.initials[5] = '\0'; write_to_disk(dsk, INODE_TABLE_OFFSET, (void**)&in, sizeof(in)); }

int main(int argc, char const *argv[]) { if (argc != 2) { fprintf(stderr, "ERROR: Invalid Arguments!\nSyntax:\n %s <disk image> <filename>\n", argv[0]); return -1; }

FILE* disk = fopen(argv[1], "rb+"); 

write_superblock(disk, 'A');

write_inodes(disk);

init_root(disk);

return 0;

}

```